Conventionally, there are brown various room temperature-curable silicone rubber compositions capable of forming rubbery elastic bodies at room temperature. A cured rubber obtained from a room temperature-curable silicone rubber composition (referred to as RTV silicone rubber composition hereunder) is superior to other organic rubbers in, for example, weather resistance, durability, heat resistance and cold resistance, and is thus used in various fields. Especially, in the field of architecture, such cured rubber is frequently used as, for example, a seal for bonding glasses; metals and glasses; and concrete joints. Further, in recent years, the cured rubber has also been widely used as a coating material for, for example, buildings, plants, and inner and outer surfaces of water pipes.
Meanwhile, once an underwater structure has been installed or in service aquatic organisms such as barnacles, sea squirts, serpulas, mussels, freshwater mussels, bryozoans, green lavers and sea lettuce that live underwater in, for example, seas and rivers will adhere to and grow on the surface of the underwater structure, ranging from a part exposed to droplets to a part underwater, which will then result in various damages. For example, when a living organism(s) has adhered to a vessel hull, the friction resistance between the bull and water will increase such that the navigation speed will drop, and that the fuel consumption will thus rise in order to maintain a constant speed, which leads to an economic disadvantage. Further, when a living organism(s) has adhered to a structure that is fixed underwater or to water surface e.g. a harbor facility, it will be difficult for such structure to fully display its unique functions, and a base member(s) thereof may be eroded as well. Furthermore, when a living organism(s) has adhered to, for example, a culturing net or a fixed net, the meshes thereof may be clogged such that fishes may die.
As a countermeasure for preventing aquatic organisms from adhering to and growing on underwater structures, there has been applied to these structures an antifouling paint prepared by combining toxic antifouling agents such as an organotin compound and cuprous oxide. Although the adhesion/growth of aquatic organisms can thus be substantially prevented by such paint, it is not preferable in terms of environmental safety and health when producing the paint and then using it to perform coating, because the paint employs toxic antifouling agents. Moreover, the usage of this paint has been legally banned due to the fact that the toxic antifouling agents gradually dissolve out of the coating film underwater, and may thus pollute waters in the long run.
Here, as a paint that has the effect of preventing the adhesion: growth of aquatic organisms, but does not contain a toxic antifouling agent(s), there has been proposed a non-toxic antifouling paint (JP-A-Sho-58-13673: Patent document 1, JP-A-Sho-62-84166: Patent document 2) that is produced by combining an RTV silicone lubber composition with a liquid paraffin or petrolatum, and is capable of imparting an antifouling, property by reducing the surface tension of the coating film. Further, there has also been proposed a non-toxic antifouling paint composition (Japanese Patent No. 2503986: Patent document 3, Japanese Patent No. 2952375: Patent document 4) capable of exhibiting an antifouling property as follows. That is, when volume contraction occurs as a reaction-curable silicone resin cures, a non-reactive polar group-containing silicone resin poor in compatibility will ooze out on the surface, coupled with the fact that the reaction-curable silicone resin itself has a low surface tension. However, the above non-toxic antifouling paint composition has environmental safety and health issues, because the non-reactive polar group-containing silicone resin poor in compatibility causes oil bleed involving a silicone resin having a polyoxyethylene group in which ethylene oxide, propylene oxide or the like has been added to a Si atom via a C—C bond; or a silicone resin with an alkoxy group being introduced to a Si atone via ethylene oxide or propylene oxide, at its molecular chain end.